#include <sys/socket.h>
#include <stdio.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sys/select.h>
#define BUF_SIZE 30
void error_handling(const char* message);
void read_routine(int sock, char* buf);
void write_routine(int sock, char* buf);


int main(int argc, char *argv[]){
    int sock;
    pid_t pid;
    char buf[BUF_SIZE];
    struct sockaddr_in serv_addr;

    if(argc!=3){
        printf("Usage : %s <IP> <port>\n", argv[0]);
        exit(1);
    }
    // step1
    sock = socket(PF_INET, SOCK_STREAM, 0);

    if(sock == -1){
        error_handling("socket() error");
    }

    // step2
    
    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(atoi(argv[2]));
    serv_addr.sin_addr.s_addr = inet_addr(argv[1]);

    // step3
    if(connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) == -1){
        error_handling("connect() error!");
    }else{
        puts("Connected........");
    }
    pid = fork();

    if(pid == 0){
        write_routine(sock, buf);
    }else{
        read_routine(sock, buf);
    }
    close(sock);
    return 0;
}
void read_routine(int sock, char* buf){
    while(1){
        int str_len = read(sock, buf, BUF_SIZE);
        if(str_len == 0){
            return;
        }

        buf[str_len] = 0;
        printf("Message from server: %s", buf);
    }
}
void write_routine(int sock, char* buf){
    while(1){
        fgets(buf, BUF_SIZE, stdin);
        if(!strcmp(buf, "q\n") || !strcmp(buf, "Q\n")){
            shutdown(sock, SHUT_WR);
            return;
        }
        write(sock, buf, strlen(buf));
    }
}
void error_handling(const char* message){
    fputs(message, stderr);
    fputc('\n', stderr);
    _exit(1);
}

